Over-expression of c-erb B-2 oncogene has been detected in human mammary carcinomas, and its presence correlated with poor prognosis and early recurrences. We will evaluate the presence of this oncogene utilizing monoclonal and polyclonal antibodies in a group of 200 patients treated at NCI in the early stage of breast cancer protocol. The information obtained by immunohistologic evaluation will be correlated with patients' outcome and other parameters such as recurrences and lymph node metastasis, in an attempt to demonstrate whether this marker can be used as a prognostic factor especially in node negative patients.